Catheter including an inner liner with a flexible distal section

ABSTRACT

In some examples, a catheter includes a catheter body including an outer jacket and an inner liner. The inner liner may include a proximal section including a proximal end of the inner liner and a distal section including a distal end of the inner liner. The distal section may include an inner liner defining a plurality of cuts. Each cut may extend at least partially through the liner wall. The one or more cuts defined in the liner wall of the distal section of the inner liner may increase a bending flexibility of the distal section relative to the proximal section of the inner liner, while maintaining a suitable tensile strength of the distal section.

This application is a continuation of U.S. patent application Ser. No.15/492,337, filed Apr. 20, 2017, and entitled, “CATHETER INCLUDING ANINNER LINER WITH A FLEXIBLE DISTAL SECTION,” the entire content of whichis herein incorporated by reference.

TECHNICAL FIELD

This disclosure relates to a medical catheter.

BACKGROUND

A medical catheter defining at least one lumen has been proposed for usewith various medical procedures. For example, in some cases, a medicalcatheter may be used to access and treat defects in blood vessels, suchas, but not limited to, lesions or occlusions in blood vessels.

SUMMARY

In some examples, a catheter includes an inner liner comprising aproximal section and a distal section, the distal section including aliner wall defining one or more cuts. The one or more cuts extend atleast partially through a thickness of the inner wall. The catheter mayalso include one or more other elements, such as, but not limited to, anouter jacket and a support member (e.g., a coil and/or a braid). The oneor more cuts defined in the liner wall of the distal section of theinner liner may increase a bending flexibility of the distal sectionrelative to the proximal section of the inner liner, while maintaining asuitable tensile strength of the distal section. This disclosure alsodescribes examples of methods of forming the catheters described hereinand methods of using the catheters.

Clause 1: In one example, a catheter includes an elongated bodyincluding an outer jacket and an inner liner, the inner lining extendingbetween a proximal end and a distal end, and the inner liner defining alumen, wherein the inner liner includes a proximal section including theproximal end and a distal section including the distal end. The distalsection of the inner liner includes a liner wall defining a plurality ofcuts, each cut extending at least partially through the liner wall.

Clause 2: In some examples of the catheter of clause 1, the lumendefined by the inner liner is an inner lumen of the elongated body.

Clause 3: In some examples of the catheter of clause 1 or 2, at leastone cut of the plurality of cuts is a through-cut that extends through athickness of the liner wall to the lumen.

Clause 4: In some examples of the catheter of any of clauses 1-3, atleast one cut of the plurality of cuts is a partial cut, wherein thepartial cut extends only partially through a thickness of the linerwall.

Clause 5: In some examples of the catheter of clause 4, the at least onecut extends from an outer surface of the liner wall and radially inwardtowards the lumen.

Clause 6: In some examples of the catheter of clause 4 or 5, the atleast one cut extends through about 20% to about 80% of the thickness ofthe liner wall.

Clause 7: In some examples of the catheter of clause 6, the at least onecut extends through about 50% of the thickness of the liner wall.

Clause 8: In some examples of the catheter of any of clauses 1-7, atleast one cut of the plurality of cuts is disposed in an arc around anouter surface of the inner liner.

Clause 9: In some examples of the catheter of any of clauses 1-8, atleast one cut of the plurality of cuts is elongated in a directionsubstantially perpendicular to a longitudinal axis of the inner liner.

Clause 10: In some examples of the catheter of any of clauses 1-9, atleast one cut of the plurality of cuts is oblong shaped, a major axis ofthe oblong shape extending in a direction substantially perpendicular toa longitudinal axis of the inner liner.

Clause 11: In some examples of the catheter of any of clauses 1-10, eachcut is elongated in a direction that define an angle from about 45degrees to about 90 degrees relative to a longitudinal axis of the innerliner.

Clause 12: In some examples of the catheter of any of clauses 1-11, atleast one cut of the plurality of cuts is elongated in a directionsubstantially parallel to a longitudinal axis of the inner liner.

Clause 13: In some examples of the catheter of any of clauses 1-12, theinner liner has a circular cross-section, and at least one cut of theplurality of cuts extends around only part of a circumference of thecircular cross-section.

Clause 14: In some examples of the catheter of clause 13, the at leastone cut extends around less than 180 degrees of the circumference.

Clause 15: In some examples of the catheter of any of clauses 1-14, theat least one cut extends around less than 90 degrees of thecircumference.

Clause 16: In some examples of the catheter of any of clauses 1-15, adensity of the plurality of cuts decreases in a proximal direction,wherein the density corresponds to a number of cuts per unit length ofthe inner liner.

Clause 17: In some examples of the catheter of any of clauses 1-16, thecuts are symmetrically arranged relative to a longitudinal axis of theinner liner.

Clause 18: In some examples of the catheter of any of clauses 1-16, thecuts are asymmetrically arranged relative to a longitudinal axis of theinner liner.

Clause 19: In some examples of the catheter of any of clauses 1-18, theplurality of cuts do not overlap with one another in a direction along alongitudinal axis of the inner liner.

Clause 20: In some examples of the catheter of any of clauses 1-19, atleast one cut of the plurality of cuts overlaps with another cut in adirection along a longitudinal axis of the inner liner.

Clause 21: In some examples of the catheter of any of clauses 1-20, theplurality of cuts form a pattern along the distal section, the patternincluding two cuts that include medial sections which are adjacent toeach other, wherein at least one end of each of the two cuts aredisplaced by a third cut.

Clause 22: In some examples of the catheter of any of clauses 1-21, theplurality of cuts form a pattern along the distal section, wherein theliner includes first and second sides of a median plane extending alonga longitudinal axis of the inner liner, and wherein the pattern includesa first set of the plurality of cuts on the first side, and a second setof the plurality of cuts on the second side, wherein the first andsecond sets mirror each other.

Clause 23: In some examples of the catheter of any of clauses 1-22, adistal-most cut of the plurality of cuts is arranged between about 0.02centimeters and about 30 centimeters from the distal end of the innerliner.

Clause 24: In some examples of the catheter of clauses 23, aproximal-most cut of the plurality of cuts is about 5 centimeters toabout 35 centimeters from the distal end of the inner liner.

Clause 25: In some examples of the catheter of any of clauses 1-24, thedistal section of the inner liner has a length of about 10 centimetersto about 30 centimeters.

Clause 26: In some examples of the catheter of clause 25, the distalsection of the inner liner has a length of about 5 centimeters to about10 centimeters.

Clause 27: In some examples of the catheter of any of clauses 1-26, alength of the distal section is smaller than a length of the proximalsection, the length being measured in a direction parallel to alongitudinal axis of the inner liner.

Clause 28: In some examples of the catheter of any of clauses 1-27, athickness of the distal section of the liner wall decreases toward thedistal end.

Clause 29: In some examples of the catheter of any of clauses 1-27, athickness of the liner wall is substantially uniform between theproximal end and the distal end.

Clause 30: In some examples of the catheter of any of clauses 1-29, theinner liner is more lubricious than the outer jacket.

Clause 31: In some examples of the catheter of any of clauses 1-30, aninner surface of the liner wall is smooth.

Clause 32: In some examples of the catheter of any of clauses 1-31, theinner liner comprises a polymer material.

Clause 33: In some examples of the catheter of clause 32, the polymermaterial includes one or more of: polytetrafluoroethylene or polyimide.

Clause 34: In some examples of the catheter of clause 32 or 33, thepolymer material includes expanded polytetrafluoroethylene.

Clause 35: In some examples of the catheter of any of clauses 1-34, theinner liner comprises a unitary liner including the distal section andthe proximal section.

Clause 36: In some examples, a catheter includes an elongated bodycomprising an outer jacket; and an inner liner extending between aproximal end and a distal end, the inner liner defining a lumen, whereinthe inner liner includes a proximal section including the proximal endand a distal section including the distal end, and wherein the distalsection of the inner liner includes a liner wall defines a helical cut.

Clause 37: In some examples of the catheter of clause 36, the lumendefined by the inner liner is an inner lumen of the elongated body.

Clause 38: In some examples of the catheter of clause 36 or 37, thehelical cut is a through-cut that extends through a thickness of theliner wall to the lumen.

Clause 39: In some examples of the catheter of any of clauses 36-38, thehelical cut is a partial cut extending only partially through athickness of the liner wall.

Clause 40: In some examples of the catheter of clause 39, the helicalcut extends from an outer surface of the liner wall and radially inwardtowards the lumen.

Clause 41: In some examples of the catheter of clause 39 or 40, thehelical cut extends through about 20% to about 80% of the thickness ofthe liner wall.

Clause 42: In some examples of the catheter of any of clauses 36-41, thehelical cut defines a helix having a pitch of about 1 millimeter to 5millimeters between adjacent turns of the cut.

Clause 43: In some examples of the catheter of any of clauses 36-42, aproximal end of the helical cut is about 5 centimeters to about 35centimeters from the distal end of the inner liner.

Clause 44: In some examples of the catheter of any of clauses 36-43, thedistal section of the inner liner has a length of about 10 centimetersto about 35 centimeters.

Clause 45: In some examples of the catheter of any of clauses 36-44, athickness of the distal section of the liner wall decreases toward thedistal end.

Clause 46: In some examples of the catheter of any of clauses 36-45, aninner surface of the liner wall is smooth.

Clause 47: In some examples of the catheter of any of clauses 36-46, theinner liner comprises a unitary liner including the distal section andthe proximal section.

Clause 48: In some examples, a method comprises forming an inner liner,the inner liner extending between a proximal end and a distal end, anddefining a lumen, wherein the inner liner includes a proximal sectionincluding the proximal end and a distal section including the distalend, and wherein the distal section of the inner liner includes a linerwall defining a plurality of cuts, each cut extending at least partiallythrough the liner wall; and positioning an outer jacket over an innerliner.

Clause 49: In some examples of the method of clause 48, forming theinner liner comprises cutting the plurality of cuts in the liner wall ofthe distal section of the inner liner.

Clause 50: In some examples of the method of clause 49, cutting theplurality of cuts in the liner wall comprises defining the plurality ofcuts with a laser cutter.

Clause 51: In some examples of the method of any of clauses 48-50,forming the inner liner includes ram extruding a polytetrafluoroethylenematerial.

Clause 52: In some examples of the method of any of clauses 48-51,forming the inner liner comprises depositing a material of the innerliner over a mask, the mask defining the plurality of cuts.

Clause 53: In some examples of the method of clause 52, depositing thematerial of the inner liner includes spraying the material onto theinner liner over the mask.

Clause 54: In some examples of the method of any of clauses 48-51,forming the inner liner comprises printing the inner liner using athree-dimensional printer.

Clause 55: In some examples of the method of any of clauses 48-54,forming the inner liner comprises: defining the plurality of cuts in atubular body defining the lumen; and, subsequently, stretching thetubular body along a longitudinal axis of the tubular body.

Clause 56: In some examples a method comprises introducing a guidemember into vasculature of a patient; and introducing a catheter in thepatient over the guide member, the catheter including an elongated bodycomprising: an outer jacket; and an inner liner extending between aproximal end and a distal end, the inner liner defining a lumen, whereinthe inner liner includes a proximal section including the proximal endand a distal section including the distal end, wherein the distalsection of the inner liner includes a liner wall defining a plurality ofcuts, each cut extending at least partially through the liner wall.

Clause 57: In some examples of the method of clause 56, the methodfurther comprises introducing a medical device into the lumen of theinner liner.

Clause 58: In some examples of the method of clause 56 or 57, the methodfurther comprises aspirating thrombus through an inner lumen of thecatheter.

Clause 59: In some examples of the method of any of clauses 56-58, themethod further comprises advancing a distal end of the catheter into anintracranial blood vessel.

Clause 60: In some examples of the method of clause 59, the methodfurther comprises removing thrombus from the intracranial blood vesselwith the catheter.

Clause 61: In some examples of the method of clause 60, removingthrombus from the intracranial blood vessel with the catheter comprisesaspirating the thrombus.

The details of one or more aspects of the disclosure are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the techniques described in this disclosurewill be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of an example catheter, which includes acatheter body and a hub.

FIG. 2 is a conceptual cross-sectional view of a part of the catheterbody of FIG. 1 including the distal end, where the cross-section istaken through a center of the catheter body and along a longitudinalaxis of the catheter body.

FIG. 3 is a conceptual cross-sectional view of a part of an exampleinner liner of the catheter body of FIG. 1, where the cross-section istaken through a center of the inner liner and along a longitudinal axisof the inner liner.

FIG. 4 is a conceptual cross-sectional view of the catheter body of FIG.1, such as taken along line A-A in FIG. 1.

FIG. 5 is a conceptual cross-sectional view of the catheter body of FIG.1, such as taken along line B-B in FIGS. 1 and 3.

FIG. 6 is a conceptual cross-sectional view of the catheter body of FIG.1, such as taken along line C-C in FIGS. 1 and 3.

FIG. 7 is a conceptual illustration of an example inner liner of acatheter body and illustrates examples of angles of cuts, where theangles are measured relative to a longitudinal axis of the inner liner.

FIG. 8 is a conceptual cross-sectional view of the inner liner of FIG. 7taken along line D-D in FIG. 7.

FIG. 9 is a conceptual cross-sectional view of a part of an exampleinner liner of a catheter body, where the cross-section is taken througha center of the inner liner and along a longitudinal axis of the innerliner.

FIG. 10 is a conceptual cross-sectional view of a catheter bodyincluding the inner liner of FIG. 9, where the cross-section is takenalong line E-E in FIG. 9.

FIG. 11 is a conceptual cross-sectional view of a part of an exampleinner liner of a catheter body, where the cross-section is taken througha center of the inner liner and along a longitudinal axis of the innerliner.

FIG. 12 is a conceptual cross-sectional view of a part of an exampleinner liner of a catheter body, where the cross-section is taken througha center of the inner liner and along a longitudinal axis of the innerliner.

FIG. 13 is a perspective view of a distal section of an example innerliner of a catheter body.

FIG. 14 is a perspective view of a distal section of another exampleinner liner of a catheter body.

FIG. 15 is a perspective view of a distal section of another exampleinner liner of a catheter body.

FIG. 16 is a perspective view of a distal section of another exampleinner liner of a catheter body.

FIG. 17 is a perspective view of a distal section of another exampleinner liner of a catheter body.

FIG. 18 is a conceptual cross-sectional view of a part of an exampleinner liner of a catheter body, where the cross-section is taken througha center of the inner liner and along a longitudinal axis of the innerliner.

FIG. 19 is a flow diagram of an example method of forming a catheter.

DETAILED DESCRIPTION

In some examples, a medical catheter (“catheter”) described hereinincludes a relatively flexible catheter body that is configured to benavigated through vasculature of a patient, e.g., tortuous vasculaturein a brain of the patient. The catheter body includes a relativelyflexible distal section that may exhibit increased flexibility relativeto a proximal portion of the catheter body. In some examples, thecatheter body includes an inner liner and an outer jacket, and theincreased flexibility of the distal section may be at least partially(e.g., partially or fully) attributable to the configuration of theinner liner. For example, a distal section of the inner liner may defineone or more cuts, which helps to increase a bending flexibility of thedistal section of the inner liner while maintaining a desirable tensilestrength of the inner liner. The one or more cuts may have any suitableconfiguration that helps to increase the bending flexibility of theinner liner while maintaining a desirable tensile strength of the innerliner and the overall catheter body. For example, the one or more cutsmay be an absence of material in or a locally thinner portion of theliner wall (e.g., a groove, divot, pocket, through-hole, or the like inan otherwise continuous surface), or may be an incision in a liner wallof the inner liner that is formed without removing material from theliner wall.

A desirable tensile strength of the inner liner or catheter body can be,for example, a minimum tensile strength for a particular use of thecatheter. Inadequate tensile strength of an inner liner or a catheterbody (of which the inner liner is part) can translate into poornavigability of the catheter body through vasculature of a patient whena clinician is advancing and retracting the catheter body in tortuousanatomy. For example, if a distal tensile strength of the inner liner orcatheter body is too low, then the distal end of the catheter may notretract from the patient at the same rate as the proximal portion of thecatheter, which may reduce the control over the catheter perceived bythe clinician. In addition, if the tensile strength of the inner liner(and, as a result, the catheter body) is too low, then the distal end ofthe catheter may remain in place while the proximal end stretches awayfrom it, which may cause a distal portion of the catheter body to breakaway from the rest of the catheter body.

The tensile strength and flexibility provided by the arrangement of theone or more cuts in an inner liner described herein may translate intobetter navigability when a clinician is advancing or retracting thecatheter, such as in tortuous anatomy. For example, the tensile strengthof the inner liners defining one or more cuts described herein may besufficiently high enough to enable the distal section of the inner linerto be retracted from a patient without compromising the structuralintegrity of the catheter body. Further, the tensile strength of theinner liners described herein may enable both the distal end and theproximal portion of a catheter body including one of the inner liners tobe retracted from the vessel of a patient at the same rate, which mayprovide the clinician with a perception of more control over thecatheter.

By using the devices and techniques herein, the tensile strength of theinner liner may be sufficiently strong enough such that distal sectionof the inner liner is capable of retracting safely, even if, forexample, the vessel around the distal end of the catheter isconstricting the catheter.

An inner liner may include a liner wall that defines an inner lumen andan outer surface of the inner liner. Each cut in the inner liner mayextend at least partially through the liner wall, e.g., at leastpartially through a thickness of the liner wall or all the way through athickness of the inner wall so as to expose an inner lumen of the innerliner. The thickness of the liner wall may be measured in a directionorthogonal to the longitudinal axis of the inner liner. In someexamples, the liner wall may be thinner at a cut, which may allow formore flexibility of the inner liner at the region including and adjacentto the cut.

In some examples in which the one or more cuts extend only partiallythrough a thickness of a liner wall of an inner liner, also referred toherein as partial cuts, the partial cuts may be defined by an outersurface of the liner wall. For example, the partial cuts may extend fromthe outer surface of the liner wall towards the inner lumen, but may notextend all the way through the liner wall to the inner lumen of theinner liner. By positioning the partial cuts on an outer surface of theliner wall, an inner surface of the inner liner may remain substantiallysmooth (e.g., smooth or nearly smooth, or without projections orindentations that would inhibit the passage of a medical device), whichmay facilitate passage of one or more medical devices (e.g., guidemembers, an embolic protection device or an embolic retrieval device,and the like) through the inner lumen of the inner liner. In otherexamples, however, the partial cuts may be defined by an inner surfaceof the liner wall in addition to, or instead of, the outer surface.

The one or more cuts defined by a distal section of an inner liner maybe arranged in any suitable pattern on the distal section of the innerliner to provide the increased flexibility of the distal section,relative to an inner liner section that is similar to the distalsection, but does not include the cuts. Example patterns formed by theone or more cuts are discussed in further detail below with reference toFIGS. 1-18.

In some examples in which the one or more cuts extend fully through athickness of a liner wall of an inner liner, also referred to herein asthrough-cuts, the one or more cuts may be arranged so as not to dividethe inner liner into physically separate portions.

An inner liner of a catheter body described herein includes a distalsection including the one or more cuts, and a proximal section. Forexample, the inner liner may consist essentially of the proximal anddistal sections. As an example, the distal section may be immediatelyadjacent to and mechanically connected to the proximal section (e.g.,formed integrally with the proximal section or formed separate from theproximal section and attached thereto).

In some examples, a catheter including the inner liner comprising adistal section defining one or more cuts may be a variable stiffnesscatheter that increases in flexibility towards a distal end of thecatheter. For example, a proximal section of the inner liner may notinclude any cuts or may have an arrangement of cuts (e.g., fewer cuts ora different pattern) different from that of the distal section, suchthat the distal section is more flexible than the proximal section. Inthis way, the cuts defined in the distal section of the inner liner mayconfigure the distal section to be more flexible than a more proximalsection of the inner liner. The variable stiffness catheter body mayallow the catheter body to exhibit a relatively high level ofpushability due to the stiffer proximal section of the inner liner whichcontributes to the overall stiffness of the catheter body, and exhibit arelatively high level of flexibility at the distal portion of thecatheter body due at least in part to the configuration of the distalsection of the inner liner.

In some examples, a catheter body of a catheter described hereinincludes an inner liner, a support element (e.g., a coil member or abraided member, or combinations thereof), and an outer jacket, which caninteract to provide a relatively flexible elongated body of the catheterwith sufficient structural integrity (e.g., column strength, which maybe a measure of a maximum compressive load that can be applied to thecatheter body without taking a permanent set) to permit the catheterbody to be advanced through the vasculature via a pushing force appliedto a proximal portion of the catheter body, e.g. without buckling,kinking, or otherwise undesirably deforming (e.g., ovalization). Adistal portion of the catheter body may lead the catheter body throughvasculature of a patient. The example inner liners described herein mayincrease the flexibility of the distal portion of the catheter body,and, therefore, may increase the navigability of the catheter bodythrough vasculature compared to a catheter including an inner liner thatis otherwise the same, but does not include the one or more cuts in adistal section.

Some catheters include catheter bodies that comprise an inner linerformed from polytetrafluoroethylene (PTFE), which may provide thecatheter body with a lubricious inner surface and allow relatively easydelivery of interventional devices through the catheter body orrelatively easy tracking of the catheter body over a guide member (e.g.,a guidewire or a microcatheter). In some cases, a PTFE inner liner mayimpart stiffness to the overall catheter body that may make the catheterbody less flexible and, therefore, less navigable through thevasculature, e.g., through the neurovasculature. While configuring aninner liner to include a distal section formed from a different, softer,or more flexible material than a proximal section of the inner liner mayhelp provide a more flexible catheter body distal section, the softer ormore flexible inner liner material may make the catheter body more proneto stretching and accordioning (e.g., the forming of multiple foldsalong a length of the inner liner and/or outer jacket). As an example,the proximal section of the inner liner may be formed from PTFE and thedistal section may be formed from a non-PTFE material that is softer andmore flexible than PTFE. The non-PTFE inner liner material may trade-offlubricity, column strength, and/or tensile strength for higherflexibility. In addition, due to the lower lubricity of non-PTFE innerliner materials compared to a PTFE inner liner, the non-PTFE inner linermay be less compatible with stentrievers or other medical devices thatmay be introduced to a treatment site through an inner lumen of theinner liner due to the relative frictional forces between the medicaldevice and the inner liner, or other mechanical interactions between themedical device and the inner liner during delivery and retrieval ofthese devices through the catheter body.

The example inner liners described herein that include one or more cutsin a distal section may increase the flexibility of the catheter body,and, therefore, may increase the navigability of the catheter bodythrough vasculature compared to a catheter including an inner liner thatis otherwise the same, but does not include the one or more cuts in adistal section. The inner liner configurations described herein mayallow a catheter body to include a PTFE inner liner without thestiffness limitations that may otherwise be associated with the PTFEinner liner. The inner liners described herein may be formed from anysuitable material in addition to or instead of PTFE.

In some examples, a catheter body may include an inner liner formed fromPTFE for a full length of the inner liner (from a proximal end to adistal end of the inner liner), and a distal section of the inner linermay include one or more cuts in the inner liner. In this way, thecatheter body may exhibit the desired lubricity provided by PTFE, whichmay provide better compatibility with stentrievers or other medicaldevices that may be introduced in the inner lumen of the inner liner,and a more flexible distal section, while maintaining stiffness at aproximal section of the inner liner. The relatively higher degree ofstiffness of the proximal section of the inner liner may help define acatheter body that has a desired level of pushability (e.g.,transmission of pushing forces applied to a proximal portion of thecatheter body to the distal portion of the catheter body). Therelatively flexible distal section may facilitate navigation of thecatheter body through vasculature of a patient by increasing theflexibility of the distal most portion of the catheter body, such thatthe catheter body may better traverse through tortuous vasculature whilestill maintaining a relatively high level of proximal pushability.

The catheter bodies described herein can be configured to exhibit arelatively high level of flexibility, pushability, torqueability, and/orstructural integrity. In some examples, a catheter body includes aninner liner including a distal section defining one or more cuts, astructural support member, and an outer jacket, which interact toprovide a flexible catheter body with sufficient structural integrity(e.g., column strength) to permit the catheter body to be advancedthrough the vasculature from a pushing force applied to a proximalportion of the catheter body, without buckling or undesirable bending(e.g., kinking) of the catheter body. In some examples, the flexiblecatheter body is configured to substantially conform to the curvature ofthe vasculature. In addition, in some examples, the catheter body has acolumn strength and flexibility that allow at least a distal portion ofthe catheter body to be navigated from a femoral artery, through theaorta of the patient, and into the intracranial vascular system of thepatient, e.g., to reach a relatively distal treatment site, includingthe middle cerebral artery (MCA), internal carotid artery (ICA), theCircle of Willis, and tissue sites more distal than the MCA, ICA, andthe Circle of Willis. The MCA and, consequently, vasculature distal tothe MCA may be relatively difficult to access due to the carotid siphonanatomy that must be traversed to reach such locations.

In some examples, the catheter may be a guide catheter that acts as aconduit to help support a microcatheter. In other examples, the cathetermay be a microcatheter. In either example, the catheter body of thecatheter may define an inner lumen, which may be configured to receiveone or more medical devices, deliver a therapeutic agent to a distaltissue site (e.g., a distal vascular site), remove thrombus (e.g., byaspiration) from the patient's vasculature, and the like or anycombination thereof. Examples of therapeutic agents include, but are notlimited to, an oxygenated medium or a pharmaceutical agent, which maybe, for example, a vasodilator such as nifedipine or sodiumnitroprusside, or a tissue plasminogen activator (t-PA), which can beused to breakdown blood clots.

In examples in which the inner lumen defined by the catheter body isused to remove thrombus from vasculature, the catheter may be referredto as an aspiration catheter. A vacuum may be applied to a proximal endof the catheter body to draw a thrombus into the inner lumen. Anaspiration catheter may be used in a medical procedure to treat anischemic insult, which may occur due to occlusion of a blood vessel thatdeprives brain tissue of oxygen-carrying blood. In some examples, inaddition to being configured to be navigated to relatively distal tissuesites, an aspiration catheter may also include a distal tipconfiguration that is configured to substantially maintain its shape,even in the presence of the vacuum force applied to the catheter duringthe aspiration process.

The catheters described herein may be advanced to a target locationwithin vasculature of the patient in cooperation with a guidewire, aninner catheter, or both, which may aid in the navigation (e.g., steeringand manipulation) of the catheter through the vasculature. For example,an inner lumen of the catheter body may be configured to receive aguidewire or an inner catheter, such that the catheter body may beguided through vasculature over the guidewire or the inner catheter. Adistal portion of an example catheter body described herein isconfigured to encourage navigability, due at least in part to the one ormore cuts in the distal section of the inner liner.

Although primarily described as being used to reach relatively distalvasculature sites, the catheters described herein may readily beconfigured to be used with other target tissue sites. For example, thecatheters may be used to access tissue sites throughout the coronary andperipheral vasculature, the gastrointestinal tract, the urethra,ureters, Fallopian tubes, and other body lumens.

FIG. 1 is a conceptual side elevation view of an example catheter 10,which includes catheter body 12 and hub 14. Catheter hub 14 ispositioned at a proximal end of catheter 10 and defines an openingthrough which an inner lumen 26 (such as shown in FIG. 2) of catheterbody 12 may be accessed and, in some examples, closed. For example,catheter hub 14 may include a luer connector for connecting to anotherdevice, a hemostasis valve, or another mechanism or combination ofmechanisms. In some examples, catheter 10 includes strain relief member11, which may be a part of hub 14 or may be separate from hub 14. Inother examples, the proximal end of catheter 10 can include anotherstructure in addition to, or instead of, hub 14.

Catheter body 12 is an elongated body that extends from proximal end 12Ato distal end 12B and defines at least one inner lumen 26 (shown in FIG.2). In some examples, catheter body 12 is elongated such that its lengthdimension (e.g., from proximal end 12A to distal end 12B is larger thanan outer diameter dimension of catheter body 12. In some examples, thelength dimension is at least 100 times larger than the outer diameterdimension. Catheter body 12 may have a single inner lumen 26, ormultiple inner lumens (e.g., two inner lumens or three inner lumens).Inner lumen 26 may terminate at any suitable point along catheter body12, which may depend on the procedure with which catheter 10 is to beused. For example, inner lumen 26 may terminate at distal opening 13defined by catheter body 12 or may terminate at an opening defined alonga side wall of catheter body 12. In some examples, an inner liner ofcatheter body 12 defines inner lumen 26. In other examples, however,another structure may be radially inward of inner lumen 26. Thus,although examples in which an inner liner of catheter body 12 definesinner lumen 26 are primarily described herein, in other examples,another structure may define inner lumen 26.

In the example shown in FIG. 1, proximal end 12A of catheter body 12 isreceived within hub 14 and is mechanically connected to hub 14 via anadhesive, welding, or another suitable technique or combination oftechniques. Opening 15 defined by hub 14 and located at proximal end 14Aof hub 14 is aligned with inner lumen 26 of catheter body 12, such thatinner lumen 26 of catheter body 12 may be accessed via opening 15.

Catheter body 12 has a suitable length for accessing a target tissuesite within the patient from a vascular access point. The length may bemeasured along longitudinal axis 16 of catheter body 12. The targettissue site may depend on the medical procedure for which catheter 10 isused. For example, if catheter 10 is a distal access catheter used toaccess vasculature in a brain of a patient from a femoral artery accesspoint at the groin of the patient, catheter body 12 may have a length ofabout 125 centimeters (cm) to about 135 cm or more, such as about 132cm, although other lengths may be used.

Catheter body 12 may be used to access relatively distal locations in apatient, such as the middle cerebral artery (“MCA”) in a brain of apatient. The MCA, as well as other vasculature in the brain or otherrelatively distal tissue sites (e.g., relative to the vascular accesspoint), may be relatively difficult to reach with a catheter, due atleast in part to the tortuous pathway (e.g., comprising relatively sharptwists or turns) through the vasculature to reach these tissue sites.Catheter body 12 may be structurally configured to be relativelyflexible, pushable, and relatively kink- and buckle-resistant, so thatit may resist buckling when a pushing force is applied to a relativelyproximal section of the catheter to advance the catheter body distallythrough vasculature, and so that it may resist kinking when traversingaround a tight turn in the vasculature. Kinking or buckling of catheterbody 12 may hinder a clinician's efforts to push the catheter bodydistally, e.g., past a turn.

As discussed in further detail below, one structural characteristic thatmay contribute to at least the flexibility of catheter body 12 is theflexible distal section of the inner liner. The flexibility of thedistal section may be at least in part due to one or more cuts (e.g.,voids) defined in a liner wall of the distal section. The pattern ofcuts may be selected to achieve the desired level of structuralintegrity (e.g., stiffness, tensile strength, and the like), whileincreasing flexibility of the distal section of the inner liner. The oneor more cuts in a distal section of the inner liner may improve thenavigability of catheter body 12 through vasculature of a patient.

In some examples, an outer diameter of catheter body 12 may be the samealong the length of catheter body 12. In other examples, an outerdiameter of catheter body 12 may taper from a first outer diameter at aproximal portion of catheter body 12 to a second outer diameter at adistal portion of catheter body 12, the second outer diameter beingsmaller than the first outer diameter. In some examples, the taper maybe continuous along the length of catheter body 12, such that an outersurface of catheter body 12 defines a smooth transition betweendifferent diameter portions. In other examples, catheter body may definediscrete step-downs in outer diameter to define the taper. The size ofthe discrete step-downs in diameter may be selected to reduce the numberof edges that may catch on anatomical features within the vasculature ascatheter body 12 is advanced through vasculature. A larger diameterproximal portion of catheter body 12 may provide better proximal supportfor catheter body 12, which may help increase the pushability ofcatheter body 12. In addition, a smaller diameter distal section mayincrease the navigability of catheter body 12 through tortuousvasculature. Thus, by reducing the outer diameter of catheter body 12 atdistal section, which leads catheter body 12 through vasculature,catheter body 12 may better traverse through tortuous vasculature whilestill maintaining a relatively high level of proximal pushability.

In some examples, the outer diameter(s) of catheter body 12 is in arange of about 3 French to about 10 French, such as about 3 French toabout 6 French. The measurement term French, abbreviated Fr or F, isthree times the diameter of a device as measured in mm. Thus, a 6 Frenchdiameter is about 2 mm.

The proximal and distal sections of catheter body 12 may each have anysuitable length. The working length of catheter body 12 may be measuredfrom distal end 14B of hub 14 to distal end 12B of catheter body 12. Insome examples, the length of the proximal section that extends fromdistal end 14B of hub 14 in the direction towards distal end 12B isabout 38.16 inches (about 96.93 cm), and the distal section has a lengthof about 11.1 inches (about 30 cm). In some examples, the distal sectionhas a length of about 10 cm to about 40 cm. In other examples, thedistal section has a length of about 5 cm to about 35 cm, such as about5 cm to about 10 cm. However, in other examples, the proximal and distalsections may have different lengths.

The diameter of inner lumen 26 (as measured in a direction perpendicularto a longitudinal axis 16 of catheter body 12) may vary based on the oneor more procedures with which catheter 10 may be used. In some examples,the diameter of inner lumen 26 (shown in FIG. 2) of catheter body 12,also referred to herein as an inner diameter (“ID”) of catheter body 12,may be substantially constant from proximal end 12A to distal end 12B.In an example, the inner diameter may be about 1.524 mm (about 0.060inches) or larger. In other examples, the inner diameter may not beconstant. For example, the inner diameter of catheter body 12 may taperfrom a first inner diameter at a proximal section that includes proximalend 12A to a second inner diameter at a distal section that includesdistal end 12B, the second inner diameter being smaller than the firstinner diameter. For example, an inner diameter of catheter body 12 maytaper from a first inner diameter of about 0.0685 inches (about 1.74 mm)to a second inner diameter of about to 0.0605 inches (about 1.54 mm).The inner diameter may, for example, gradually taper in the directionalong longitudinal axis 16, where the taper can be linear, curved,continuous or discontinuous; e.g., the inner diameter of catheter body12 may step-down from the first inner diameter to the second innerdiameter in discrete steps.

Catheter body 12 can be relatively thin-walled, such that it defines arelatively large inner diameter for a given outer diameter, which mayfurther contribute to the flexibility and kink-resistance of catheterbody 12. The wall thickness of catheter body 12 may be the differencebetween the outer diameter of catheter body 12 and the inner diameter ofcatheter body 12, as defined by inner lumen 26. The wall thickness ofcatheter body 12 may also be referred to as the thickness of theelongate body, such as T_(CB) in FIG. 4.

In some examples, catheter body 12 may be formed from two or morediscrete and separate longitudinally extending segments that aremechanically connected to each other, e.g., at axial butt joints. Inother examples, catheter body 12 may be substantially continuous along alength of catheter body 12. For example, the inner liner of catheterbody 12 may continuously extend from proximal end 12A to distal end 12Bof catheter body 12, and a structural support member may span at leastpart of catheter body 12. A substantially continuous catheter body 12may be better configured to better distribute forces in a longitudinaldirection (in a direction along longitudinal axis 16) and rotationaldirection (rotation about longitudinal axis 16) compared to a catheterbody including two or more longitudinally extending segments that aremechanically connected to each other. Thus, the substantially continuousconstruction of catheter body 12 may contribute to the ability of body12 to transfer axial pushing forces from the proximal portion ofcatheter body 12 to the distal section, as well transfer rotationalforces (if any) applied from the proximal portion of catheter body 12 tothe distal portion of catheter body 12.

While in some examples, catheter body 12 includes an outer jacket formedof two or more longitudinally extending segments that are in an abuttingrelationship, due to the continuous inner liner and, in some examples,the structural support member that extends along a majority of thelength of catheter body 12, catheter body 12 may still better distributeforces and flexibility compared to a catheter body including two or morelongitudinal sections that are mechanically connected to each other. Insome examples, the outer jacket is formed of a single segment. The innerliner or structural support member that extends through at least a partof the proximal section and at least part of distal portion of catheterbody 12 may provide sufficient continuity to catheter body 12 to provideit with the desired force distribution characteristics for facilitatingpushing of catheter body 12 to relatively distal tissue sites (e.g.,distal vascular sites), and for facilitating rotational movement ofcatheter body 12.

In some examples, at least a portion of an outer surface of catheterbody 12 includes one or more coatings, such as, but not limited to, ananti-thrombogenic coating, which may help reduce the formation ofthrombi in vitro, an anti-microbial coating, or a lubricating coating.The lubricating coating may be configured to reduce static friction orkinetic friction between catheter body 12 and tissue of the patient ascatheter body 12 is advanced through the vasculature. In addition, orinstead, in some examples, the lubricating coating may be configured toreduce static or kinetic friction between catheter body 12 and anothercatheter through which catheter body 12 may be inserted. The lubricatingcoating can be, for example, a hydrophilic coating. In some examples,the entire working length of catheter body 12 (from distal section 14Bof hub 14 to distal end 12B) is coated with the hydrophilic coating. Inother examples, only a portion of the working length of catheter body 12coated with the hydrophilic coating. This may provide a length ofcatheter body 12 distal to distal end 14B of hub 14 with which theclinician may grip catheter body 12, e.g., to rotate catheter body 12,pull catheter body 12 when removing catheter body 12 from the patient,or push catheter body 12 through vasculature.

FIG. 2 is a conceptual cross-sectional view of a part of a distalportion of catheter body 12 including distal end 12B, where thecross-section is taken through a center of catheter body 12 and alonglongitudinal axis 16 of catheter body 12. In some examples, catheterbody 12 may be a tubular body, such that the cross-section shown in FIG.2 illustrates one half of the tubular body. Catheter body 12 includesinner liner 18, which comprises liner wall 19 defining a plurality ofcuts 20. In addition, the depicted catheter body 12 includes outerjacket 24, and support member 28. Inner liner 18 may define lumen 26,which extends from distal opening 13 at distal end 12B of catheter body12 to proximal end 12A.

Lumen 26 may be sized to receive a medical device (e.g., anothercatheter, a guide member, an embolic protection device, a stent, athrombectomy device, or any combination thereof), a therapeutic agent,or the like. At least the inner surface of inner liner 18 defining innerlumen 26 may be lubricious in some examples to facilitate theintroduction and passage of a device, a therapeutic agent, or the like,through lumen 26. For example, the material from which the entire innerliner 18 is formed may be lubricious. In addition to, or instead of,being formed from a lubricious material, in some examples, an innersurface of inner liner 18 is coated with a lubricious coating.

Examples of materials from which inner liner 18 may be formed include,but are not limited to, PTFE, expanded PTFE (ePTFE, e.g., unidirectionalePTFE or bi-directional ePTFE), a fluoropolymer, perfluoroalkyoxy alkane(PFA), fluorinated ethylene propylene (FEP), or any combination thereof.A unidirectional ePTFE may be stretched in one of the longitudinal orradial directions, and a bi-directional ePTFE may be stretched in boththe longitudinal and radial directions. Other examples of materials fromwhich inner liner 18 may be formed include, but are not limited to, LowDensity Polyethylene (LDPE) (e.g., about 42D), a PTFE having a durometerof about 60D, High Density Polyethylene (HDPE), or any combinationthereof. Some such polyolefin materials may have similar coefficients offriction as PTFE, and may be conducive to processing.

Inner liner 18 includes proximal section 18A and distal section 18B.Distal section 18B includes a distal end of inner liner 18, which in theexample shown in FIG. 2 is co-extensive with distal end 12B of catheterbody 12. In other examples, the distal end of inner liner 18 may beproximal to distal end 12B of catheter body 12 or may extend distal toouter jacket 24. Distal section 18B may have any suitable length. Insome examples, distal section 18B is about 5% to about 50% of a totallength of inner liner 18, such as about 10% to about 40%, about 5% toabout 25%, or about 10% to about 25% of the total length of inner liner18. In some examples, distal section 18B has a length of about 5 cm toabout 40 cm, such as about 5 cm to about 35 cm, or about 5 cm to about10 cm. In some of these examples, inner liner 18 has a total length ofabout 132 cm.

Proximal section 18A includes a proximal end of inner liner 18, whichmay be co-extensive with distal end 12B of catheter body 12. In otherexamples, the proximal end of inner liner 18 may be proximal to proximalend 12B of catheter body 12 or may be distal to proximal end 12B.Proximal section 18A and distal section 18B may have different lengthsin some examples, e.g., proximal section 18A may be longer than distalsection 18B or proximal section 18A may be shorter than distal section18B. In other examples, proximal section 18A and distal section 18B maysubstantially equal (e.g., equal or nearly equal) lengths.

In some examples, inner liner 18 consists essentially of proximalsection 18A and distal section 18B. For example, proximal section 18Aand distal section 18B may together extend the entire length of innerliner 18, as measured along longitudinal axis 16. In these examples,proximal section 18A may end where distal section 18B begins. In someexamples, proximal section 18A and distal section 18B may be formed asseparate structures, and then attached together at a butt joint oranother suitable joint.

In other examples, proximal section 18A and distal section 18B may havea unitary body construction, e.g., may be formed as one body, such thatliner wall 19 is continuous along the entire length of inner liner 18,such that inner liner 18 is a single, seamless tubular body. A seamlessinner liner 18 may, for example, be devoid of any seams (e.g., the seamformed from joining two separate tubular bodies together at an axiallocation along longitudinal axis 16), such that the seamless inner liner18 is a unitary body, rather than multiple, discrete bodies that areseparately formed and subsequently connected together. A seamless innerliner 18 may be easier to slide over another device, e.g., a guidemember, compared to a catheter formed from two or more longitudinalsections that are mechanically connected to each other because theseamless inner liner may define a smoother inner lumen 26. In contrast,joints between sections of an inner liner that are formed from two ormore longitudinal sections may define surface protrusions or otherirregularities along inner lumen 26 which may interfere with the passageof devices through inner lumen 26. In addition, a seamless inner liner18 may help distribute pushing and rotational forces along the length ofcatheter body 12. Thus, the seamless inner liner 18 may help contributeto the pushability of catheter body 12.

In some examples, a thickness of liner wall 19 of inner liner 18 issubstantially constant along a length of inner liner 18. In otherexamples, the thickness of liner wall 19 varies along a length of innerliner 18. For example, the thickness of liner wall 19 may decreasetoward the distal end (e.g., the thickness of liner wall 19 may decreasefrom the proximal end to the distal end of inner liner 18, or maydecrease from a proximal end of distal section 18B to a distal end ofdistal section 18B). For example, the thickness of liner wall 19 maydecrease from about 0.33 millimeters (mm) at the proximal end of innerliner 18 to about 0.0127 mm (about 0.0005 inches) at the distal end ofinner liner 18. However, other wall thicknesses may be used in otherexamples, and may depend on the particular procedure for which catheter10 is used.

In the example of FIG. 2, liner wall 19 in distal section 18B of innerliner 18 defines a plurality of cuts 20. In other examples, liner wall19 in distal section 18B may define only one cut, e.g., a helical cut oranother cut configuration that extends along a length of distal section18B. Although not shown in FIG. 2, in some examples, liner wall 19 inproximal section 18A of inner liner 18 may also define one or more cuts.However, in other examples, liner wall in proximal section 18A does notdefine any cuts. Regardless of whether proximal section 18A includes oneor more cuts, distal section 18B of inner liner 18 may be more flexiblethan proximal section 18A, e.g., due to the presence and/or pattern ofthe one or more cuts 20, due to the material from which distal section18B is formed, or any combination thereof.

In the example of FIG. 2, cuts 20 extend only partially through linerwall 19, and do not extend through an entire thickness of liner wall 19(measured in a direction perpendicular to longitudinal axis 16 ofcatheter body 12, which may also be a longitudinal axis of inner liner18). The depth of the partial cut 20 may be described as a percentage ofthe thickness of liner wall 19 or as a unit of length (e.g.,millimeters). In some examples, the depth of a partial cut 20 may beabout 20% to about 80% of the thickness of liner wall 19, such as about50% to about 75% of the thickness of liner wall 19. In contrast, athrough-cut 20 may extend through 100% of the thickness of liner wall19.

In examples in which cuts 20 include a plurality of partial cuts, eachpartial cut may have a substantially similar depth or at least two ofthe partial cuts may have different depths. For example, each of thepartial cuts may have the same depth as measured as a unit length. Asanother example, the unit length of the depths of the partial cuts maybe different, but the depth as measured as a percentage of the thicknessof liner wall 19 may be the same. If inner liner 18 is stretched duringa manufacturing process, then a partial cut at a more distal portion ofinner liner 18 may have a smaller depth in millimeters than a moreproximal cut; however, the percentage of thickness of the depth of thetwo cuts may be substantially the same (e.g., equal or within 5% of eachother)

In some examples in which cuts 20 are partial cuts, cuts 20 extend froman outer surface of liner wall 19 toward lumen 26, where the outersurface may be the surface closest to outer jacket 24 or other outerlayer or surface of catheter body 12. In these examples, the innersurface of inner liner 18 defining lumen 26 may be relatively smooth,which may help facilitate the passage of medical devices through lumen26. For example, a guide member may not catch on a cut 20 as it is beingtraversed through inner lumen 26 from proximal end 12A of catheter body12 towards the distal end 12B. In other examples, cuts 20 may extendfrom an inner surface of liner wall 19, which defines lumen 26, towardsthe outer surface. In some of these examples, the cuts can be configuredto minimize interference with a medical device being traversed throughlumen 26. For example, an angular orientation of the cuts relative to anaxis that runs orthogonal to longitudinal axis 16 may be selected tominimize the possibility that a guide member will catch on the cut.

Although inner liner 18 defining a plurality of cuts 20 is primarilydescribed herein, in some examples, inner liner 18 may define only onecut, which may extend along a length (e.g., 5 cm to about 30 cm, such asabout 5 cm to about 15 cm) of distal section 18B. For example, thesingle cut may be helically shaped and wrap around a perimeter of innerliner 18.

Cuts 20 may be positioned along any suitable length of distal section18B. For example, a distal-most cut 20 may be proximal to distal end 12Bof catheter body 12, as shown in FIG. 2. In some examples, thedistal-most cut 20 (or, in the case of a helical cut, a distal end ofthe helical cut) may be relatively close to distal end 12B, such asabout 0.2 mm to about 30 mm (e.g. about 0.254 mm (about 0.010 inches) toabout 5 mm) from distal end 12B. A proximal-most cut 20 (or, in the caseof a helical cut, a proximal end of the helical cut) may be, forexample, about 5 cm to about 35 cm (e.g., about 6.6 cm to about 33 cm)from distal end 12B.

The one or more cuts 20 are configured to increase a bending flexibilityof inner liner 18 and catheter body 12, e.g., such that distal end 12Bmay move relative to proximal end 12A or relative to an intermediateportion of catheter body 12. To facilitate this, the one or more cuts 20may have any suitable arrangement relative to inner liner 18 and to eachother if more than one cut 20 is defined in liner wall 19. In theexample of FIG. 2, cuts 20 may be in the pattern shown in FIG. 13 or mayhave another pattern. In examples in which multiple cuts 20 are definedin liner wall 19, inner liner 18 can include any suitable number ofcuts. In the example of FIG. 2, eight cuts 20 are shown on one side oflongitudinal axis 16, and eight cuts 20 are shown on the other side oflongitudinal axis 16. However, FIG. 2 may also illustrate an example inwhich inner liner 18 includes eight cuts that extend on side oflongitudinal axis 16. In other examples, however, inner liner 18 mayhave another number and/or arrangement of cuts 20.

In some examples, each of the cuts 20 has the same configuration, suchas the same shape and size. A size of a cut 20 may be defined by adepth, a length, and a width of the cut, which may be used to determinea volume of the cut. The width of a cut 20 may be measured in adirection along longitudinal axis 16. The depth may be measured in adirection perpendicular to longitudinal axis 16 or, in the case of a cuthaving a depth oriented at a non-perpendicular angle relative tolongitudinal axis 16 in another direction that starts from the outerinner surface of liner wall 19 and towards or away from, respectively,inner lumen 26. The length of the cut measured from one end of the cutto the other end. In other examples, one cut 20 may have differentconfigurations from at least one other cut 20. In some examples, a cut20 may be oblong shaped, such that a major axis of the oblong shapeextends in a direction substantially perpendicular to longitudinal axis16. An oblong shaped cut may include, for example, an elongatedrectangle, an elongated oval, ellipse, or the like.

Cuts 20 may define a pattern (also referred to herein as a cut pattern).The pattern may be symmetrical or asymmetrical. For example, cuts 20 maybe symmetrically arranged relative to longitudinal axis 16, e.g., mayhave radial symmetry. Other types of symmetric patterns may be used forcuts 20, such as, but not limited to, reflection, rotational, glidereflection, or helical symmetry. In some examples, inner liner 18 maydefine a symmetrical cut pattern along one portion of distal section 18Band an asymmetrical cut pattern along a different portion of distalsection 18B.

In some examples, inner liner 18 may include only one cut that windshelically around inner liner 18. The helical cut may define a helixhaving a pitch of about 1 mm to about 5 mm between adjacent turns of thecut, although a helical cut having other configurations may be used inother examples. In other examples, the pattern may be defined bymultiple cuts in a repeated arrangement along a length of inner liner18. For example, multiple sets of cuts may be positioned along thelength of inner liner 18, each set including one or more cuts positionedaround a perimeter (e.g., a circumference) of inner liner 18. In someexamples, each set of cuts may be offset from an adjacent setcircumferentially and/or longitudinally. Examples cut patterns aredescribed with respect to FIGS. 13-17.

In some examples, each cut 20 does not overlap with any other cut 20. Inother examples, at least one cut 20 overlaps with another cut 20. Forexample, a cut pattern may include a double helix shape, such as a firsthelical partial cut rotating counterclockwise along a length of thedistal section, and a second helical partial cut rotating clockwisealong the same length of the distal section, such that the two cutsoverlap at multiple points along the distal section. As another example,two non-helical cuts may overlap to form an “X” shape.

Cuts 20 may have a density, which may be the number of cuts 20 per unitlength of inner liner 18 (the length being measured in a direction alonglongitudinal axis 16). If inner liner 18 defines a single cut 20, e.g.,a single helically shaped cut, then the density of the cut maycorrespond to a number of turns the cut makes around an outer (or inner)circumference of inner liner 18 per a length of inner liner 18.

In some examples, the density of cuts 20 may be the same along a lengthof inner liner 18. In other examples, however, the density of cuts 20may vary along the length of inner liner 18. For example, the density ofcuts 20 may increase in the distal direction, such that there are morecuts 20 near a distal end of inner liner 18 than near the proximal end.In these examples, for an inner liner 18 that is otherwise the same, adistal portion of distal section 18B of inner liner 18 may have agreater bending flexibility than a more proximal portion of distalsection 18B. In another example, the density of cuts 20 may decrease inthe distal direction, such that there are fewer cuts 20 near a distalend of inner liner 18 than near the proximal end. In these examples, foran inner liner 18 that is otherwise the same, a distal portion of distalsection 18B of inner liner 18 may be stiffer than a more proximalportion of distal section 18B.

In some examples, the density of cuts 20 on inner liner 18 may be about4% to about 30% (e.g., such as about 5% to about 25%, about 11% to about19%, or about 14%). That is, about 4% to about 30% of inner liner 18 maybe cut. The percentage of inner liner 18 that is cut may be, forexample, a percentage of an area of an outer surface of inner liner 18.

Inner liner 18 defining cuts 20 may be formed using any suitabletechnique. In some examples, cuts 20 may be etched, laser cut, ormechanically cut via a blade, router, abrasion disk, or the like into atubular body or other material from which inner liner 18 is formed. Inother examples, inner liner 18 may be formed by winding a ribbon of aninner liner material (e.g., PTFE) around a beading. As another example,inner liner 18 may be formed using an additive manufacturing process(also referred to as a three-dimensional printing technique in someexamples). Cuts 20 may then be defined during the additivemanufacturing.

Support member 28 is configured to increase the structural integrity ofcatheter body 12 while allowing catheter body 12 to remain relativelyflexible. For example, support member 28 may be configured to helpcatheter body 12 substantially maintain its cross-sectional shape or atleast help prevent catheter body 12 from buckling or kinking as it isnavigated through tortuous anatomy. In some examples, catheter body 12may include another layer, such as a support layer (not shown in FIG. 2)that adheres support member 28 to one or both inner liner 18 or outerjacket 24. Support member 28, together with inner liner 18, and outerjacket 24, may help distribute both pushing and rotational forces alonga length of catheter body 12, which may help prevent kinking of catheterbody 12 upon rotation of body 12 or help prevent buckling of body 12upon application of a pushing force to body 12. As a result, a clinicianmay apply pushing forces, rotational forces, or both, to the proximalportion of catheter body 12, and such forces may cause a distal portionof catheter body 12 to advance distally, rotate, or both, respectively.

In the example of FIG. 2, support member 28 extends along only a portionof a length of catheter body 12. For example, a proximal end of supportmember 28 may be positioned distal to distal end 14B of hub 14 (or ofstrain relief 11) and a distal end of support member 28 may bepositioned at distal end 12B of catheter 12 or proximal to distal end12B. In other examples, a proximal end of structural support member 28may be positioned proximal to distal end 14B of hub 14 and a distal endof member 28 be positioned at distal end 12B of catheter 12 or proximalto distal end 12B. In some examples, support member 28 may be fully orpartially co-extensive with distal section 18B of inner liner 18. Insome these examples, support member 28 may be arranged relative to innerliner 18 so that support member 28 does not sit in or otherwise cover acut 20. In other examples, support member 28 may not be coextensive withdistal section 18B, i.e., may be proximal to the entire distal section18B. Further, in other examples, catheter body 12 may not includesupport member 28.

In some examples, support member 28 includes a generally tubular braidedstructure, a coil member defining a plurality of turns, e.g., in theshape of a helix, or a combination of a braided structure and a coilmember. Thus, although examples of the disclosure describe supportmember 28 as a coil, in some other examples, the catheter bodiesdescribed herein include a braided structure instead of a coil or abraided structure in addition to a coil. For example, a proximal portionof support member 28 may include a braided structure and a distalportion of structural support member 28 may include a coil member.Support member 28 can be made from any suitable material, such as, butnot limited to, a metal (e.g., a nickel titanium alloy (Nitinol) orstainless steel), a polymer, a fiber, or any combination thereof.

Support member 28 may be coupled, adhered, or mechanically connected toat least a portion of an outer surface of inner liner 18, such as via asupport layer. The support layer may be a thermoplastic material or athermoset material, such as a thermoset polymer or a thermoset adhesive.In some cases, the material forming the support layer may have elasticproperties, such that there may be a tendency for the support layer toreturn to a resting position. In some examples, the support layer ispositioned between the entire length of support member 28 and innerliner 18. In other examples, the support layer is only positionedbetween a part of the length of support member 28 and inner liner 18.

Outer jacket 24 is positioned radially outward of inner liner 18 andsupport member 28, and may be positioned around or covers at least apart or all of both inner liner 18 and support member 28. The supportmember 28 is positioned between inner liner 18 and outer jacket 24 in atleast some portions of catheter body 12. In some examples, outer jacket24 defines the outer surface of catheter body 12. Although a coating oranother material may be applied over the outer surface of outer jacket24, outer jacket 24 may still substantially define shape and size of theouter surface of catheter body 12. Outer jacket 24, together with innerliner 18 and support member 28, may be configured to define catheterbody 12 having the desired flexibility, kink resistance, torqueresponsiveness, structural integrity, and pushability characteristics.

Outer jacket 24 may have stiffness characteristics that contribute tothe desired stiffness profile of catheter body 12. For example, outerjacket 24 may be formed to have a stiffness that decreases from aproximal end 12A of catheter body 12 to distal end 12B. For example,outer jacket 24 may be formed from two or more different materials thatenable outer jacket 24 to exhibit the desired stiffness characteristics.In some examples, outer jacket 24 may define a durometer gradient alonglongitudinal axis 16. For example, outer jacket 24 may be defined by aplurality of tubular segments extending from proximal end 12A to distalend 12B wherein each tubular segment defines a different durometer. Thedurometer gradient of outer jacket 24 may be selected to help providecatheter body 12 with the desired flexibility characteristics. Forexample, in some examples in which catheter body 12 increases inflexibility from proximal end 12A towards distal end 12B, the durometergradient of outer jacket 24 may decrease in a direction from proximalend 12A towards distal end 12B. In some examples, the durometer gradientof outer jacket 24 may decrease in a direction from proximal end 12Atowards distal end 12B and then increase just proximate of distal end12B to provide an increased flexibility about distal portion 17B whilealso increasing the hardness about distal opening 13 to resist geometricdeformation when distal opening 13 (FIG. 1) of catheter body 12 isengaged with a guide member, which may help support the navigation ofcatheter body 12 through vasculature. In some examples, the durometer ofouter jacket 24 may be from about 25D to about 75D. For example, outerjacket 24 may define a durometer gradient from proximal end 12A towardsdistal end 12B that generally decreases from about 75D to about 25D,with a distal segment defining distal opening 13 having a durometergreater than 25D (e.g., 55D).

Example materials that may be used to form outer jacket 24 include, butare not limited to, polymers, such as a polyether block amide (e.g.,PEBAX®, commercially available from Arkema Group of Colombes, France),an aliphatic polyamide (e.g., Grilamid®, commercially available fromEMS-Chemie of Sumter, S.C.), another thermoplastic elastomer,polyurethanes, or other thermoplastic material, or combinations thereof.

In some examples, at least a portion of an outer surface of outer jacket24 includes one or more coatings, such as, but not limited to, ananti-thrombogenic coating, which may help reduce the formation ofthrombi in vitro, an anti-microbial coating, and/or a lubricatingcoating.

FIG. 3 is a conceptual cross-sectional view of a part of inner liner 18,where the cross-section is taken through a center of inner liner 18 andalong longitudinal axis 16. In the example shown in FIG. 3, cuts 20defined in liner wall 19 of inner liner 18 include cuts 20A and 20B.Cuts 20A, 20B are partial cuts that only extend partially through athickness of liner wall 19. In some examples, cuts 20A, 20B are separatecuts that are axially aligned along longitudinal axis 16 andcircumferentially spaced from each other by a part of liner wall 19. Inother examples, cuts 20A, 20B may be part of a common cut and may becontinuous with each other, e.g., may extend partially or fully aroundan outer perimeter of inner liner 18.

FIGS. 4-6 illustrate respective conceptual cross-sectional views ofcatheter body 12. FIG. 4 is a conceptual cross-sectional view ofcatheter body 12 of FIG. 1 taken along line A-A in FIG. 1. In anexample, line A-A is positioned in proximal section 18A of inner liner18. FIG. 4 illustrates a thickness of outer jacket 24 (T_(OJ)), athickness of inner liner 18 (T_(IL)), and the thickness of catheter body12 (T_(CB)). In the example shown in FIG. 4, proximal section 18A ofinner liner 18 does not define any cuts through a thickness T_(IL) ofinner liner 18 (which may also be a thickness of liner wall 19).

In the example shown in FIG. 4, the total thickness T_(CB) of catheterbody 12 is equal to the thickness T_(IL) of inner liner 18 plus thethickness T_(OJ) of outer jacket 24. In some examples in which catheterbody 12 includes support member 28, support member 28 may also be seenin the cross-sectional view shown FIG. 4, positioned between inner liner18 and outer jacket 24. In some of these examples, support member 28 mayalso contribute to the total thickness T_(CB) of catheter body 12. Inother examples, however, support member 28 may be embedded in one orboth of inner liner 18 or outer jacket 24, and, therefore, may notcontribute to the total thickness T_(CB) of catheter body 12.

As discussed above, cuts 20 defined by distal section 18B of inner liner18 may have any suitable arrangement relative to each other. In someexamples, a plurality of cuts 20 are aligned along longitudinal axis 16and distributed around a circumference of inner liner 18. An example ofsuch an arrangement is shown in FIG. 5, which is a conceptualcross-sectional view of catheter body 12 taken along line B-B in FIGS. 1and 3. FIG. 5 illustrates a cross-section of a portion of distal section18B of inner liner 18 that defines some of the cuts 20. In the exampleshown in FIG. 5, cuts 20 defined in liner wall 19 of inner liner 18include cuts 20A-20E, which are aligned along longitudinal axis 16, and,therefore shown in the cross-sectional view of FIG. 5. Cuts 20A-20E arealso circumferentially distributed around an outer perimeter of innerliner 18. As shown in FIGS. 3 and 5, cuts 20A and 20B may be at leastpartially diametrically opposed to one another. However, as discussedwith respect to FIGS. 13-18, inner liner 18 may have a differentarrangement of cuts 20 in other examples.

FIG. 6 is a conceptual cross-sectional view of catheter body 12 takenalong line C-C in FIGS. 1 and 3, and illustrates a cross-section of aportion of distal section 18B of inner liner 18 that does not includeany cuts 20. In an example, thickness T_(IL) of inner liner 18 issubstantially uniform between the proximal and distal ends of innerliner 18. This may mean, for example, that although cuts 20 are presentin distal section 18B of inner liner 18, a thickness of liner wall 19 ata position where there are no cuts 20 may be substantially the same as athickness of liner wall 19 in proximal section 12A. In an example, thismay mean that inner liner 18 has substantially similar cross-sections atlines A-A and C-C (FIGS. 1 and 3), even though the thickness of linerwall 19 is different at line B-B (e.g., FIGS. 1 and 3). In otherexamples, a thickness of inner liner 18 may not be uniform alonglongitudinal axis 16 (e.g., in the case of a tapering inner liner 18).

As shown in FIGS. 5 and 6, in the portion of distal section 18B of innerliner 18 that defines one or more cuts 20, inner liner 18 has a recuedthickness T_(REDUCED) compared to thickness T_(IL). As a result of thisreduced thickness T_(REDUCED), an overall stiffness of distal section18B of inner liner 18 may be reduced, thereby allowing distal section18B to flex (e.g., bend) more readily in response to a given externalforce compared to an inner liner having a constant thickness T_(IL).

Inner liner 18 may define a substantially constant (e.g., identical ornearly identical) inner diameter along the entire length of inner liner18, while in other examples, inner liner 18 may define different innerdiameters. For example, proximal section 18A of inner liner 18 maydefine a first inner diameter and distal section 18B may define a secondinner diameter, the second inner diameter being smaller than the firstinner diameter. For example, inner liner 18 may taper continuously fromthe first inner diameter to the second inner diameter, or may define oneor more step-downs in inner diameter along the length of inner liner 18.

Cuts 20 defined in liner wall 19 of inner liner 18 may have differentangular orientations relative to longitudinal axis 16 of catheter body12 (or of inner liner 18). FIGS. 7 and 8 are conceptual illustrations ofinner liner 18 and provide frameworks for describing the angularorientations of cuts 20 relative to longitudinal axis 16. FIG. 7illustrates a framework for describing the angular orientations of cuts20 in a plane that extends in a longitudinal direction, e.g., in adirection along longitudinal axis 16. In the framework shown in FIG. 7,the angular orientation of longitudinal axis 16 corresponds to 0degrees. A longitudinal angle that is orthogonal to longitudinal axis 16is 90 degrees, either clockwise or counterclockwise, as shown in FIG. 7.

In some examples, cuts 20 define arc segments that are elongated in adirection relative to longitudinal axis 16, such that the ends of thecut are not axially aligned along longitudinal axis 16, but, rather, maybe axially displaced and, in some examples, circumferentially displacedfrom each other. For example, one or more cuts 20 may be elongated in adirection that includes angles from about 45 degrees to about 90 degreesrelative to longitudinal axis 16. As another example, one or more cuts20 may be elongated in a direction that includes angles less than 45degrees relative to longitudinal axis 16. Other examples, cuts 20 may bedisposed around inner liner 18, such that a cut has an arc segment thatis perpendicular to longitudinal axis 16, e.g., cut 20A of FIG. 5. Insome examples, at least one of cuts 20 may be elongated in a directionsubstantially perpendicular to longitudinal axis 16 (e.g., from about 85degrees to about 95 degrees relative to longitudinal axis 16 such as 88degrees to 92 degrees relative to longitudinal axis 16, or 90 degreesrelative to longitudinal axis 16). In some examples, at least one ofcuts 20 may be elongated in a direction substantially parallel tolongitudinal axis 16 (e.g., about −5 degrees to about 5 degrees relativeto longitudinal axis 16 such as −2 degrees to 2 degrees relative tolongitudinal axis 16, or 0 degrees relative to longitudinal axis 16).

In some examples, a cut 20 may be oriented such that a maximum depth ofthe cut is along an axis that is oriented about 90 degrees in theangular framework shown in FIG. 7. In other examples, a cut may beoriented such that a maximum depth of the cut is along an axis that isoriented less than 90 degrees relative to longitudinal axis 16, e.g.,about 15 degrees to about 89 degrees in either the clockwise (cw)direction or the counterclockwise (ccw) direction.

FIG. 8 is a conceptual cross-sectional view of inner liner 18 of FIG. 7,where the cross-section is taken in a direction perpendicular tolongitudinal axis 16. The angles illustrated in the example of FIG. 8are shown around a circumference of inner liner 18, and illustrate aframework for describing the circumferential position of, e.g., a cut 20or a plurality of cuts relative to each other, as well as an orientationof the cut in a depth direction. In some examples, a cut 20 may beextend less than 360 degrees around a circumference of inner liner 18,such as, but not limited to, about 30 degrees to about 180 degrees. Inthese examples, the cut 20 may not be elongated relative to longitudinalaxis 16 or may be elongated relative to longitudinal axis 16 (e.g., theends of the cut may be longitudinally offset from each other). When acut is not relative to longitudinal axis 16, the cut may have a90-degree orientation (as shown in FIG. 7) relative to longitudinal axis16.

In other examples a cut may extend about 360 degrees around acircumference of the inner liner, but due to the elongation of the cut,the cut does not divide inner liner 18 into physically separateportions.

In some examples, at least some cuts 20 may be arranged with radialsymmetry, such that the at least some cuts 20 are equidistant from oneanother around a circumference of inner liner 18. However, in otherexamples, cuts 20 may be radially asymmetrical. When cuts 20 aredescribed as being circumferentially aligned in some examples, the cuts20 may have the same angular position, a framework for describing theangular position being shown in FIG. 8.

FIGS. 9-18 illustrate other example configurations of cuts defining aninner liner of catheter body 12. Each of the inner liners shown in FIGS.9-18 may be similar to inner liner 18, but have a different cutconfiguration or pattern.

FIGS. 2,3, and 5 illustrate an example inner liner 18 defining cuts 20that extend only partially through a thickness of liner wall 19. Asdiscussed above, in other examples, inner liner 18 may definethrough-cuts instead of or in addition to partial cuts. For example, anexample inner liner may comprise only partial cuts or only through-cuts.As another example, an example inner liner may comprise both partialcuts and through-cuts, such that a percentage of the cuts are partialcuts, and another percentage of the cuts are through-cuts. For example,an example inner liner 18 may comprise about 50% through-cuts and about50% partial cuts, or any other percentage combination.

FIGS. 9 and 10 illustrate an example inner liner 30 that defines aplurality of through-cuts 32. FIG. 9 is a conceptual cross-sectionalview of a part of an example inner liner 32 of a catheter body, wherethe cross-section is taken through a center of inner liner 32 and alonga longitudinal axis 16 of inner liner 30. FIG. 10 is a conceptualcross-sectional view of an example of a catheter body that includesinner liner 30 and outer jacket 24, where the cross-section of innerliner 30 is taken through a through-cut 32 along line E-E in FIG. 9. Asshown in FIGS. 9 and 10, through-cut 32 extends through a thickness of aliner wall of inner liner 30 from inner lumen 26 defined by inner liner30 to an outer surface of inner liner 30.

As discussed above, cuts 20 defined in inner liner 18 may have anysuitable configuration. For example, FIG. 2 illustrates example cuts 20that have a rectangular shape in a cross-section taken alonglongitudinal axis 16. FIGS. 11 and 12 illustrate other example cutconfigurations.

FIG. 11 is a conceptual cross-sectional view of a part of an example ofinner liner 36, where the cross-section is taken through a center ofinner liner 36 and along a longitudinal axis 16 of inner liner 36. Aliner wall of inner liner 36 defines a plurality of cuts 38, which areeach a partial cut having a curved shape in cross-section. For example,walls 40, 42 of cut 38 are concave and a bottom surface 44 of cut 38 isrelatively flat. In some examples, cut 38 has a smooth inner surface. Adepth of cut 38 may be measured, for example, from an outer surface 36Aof inner liner 36 to bottom surface 44.

FIG. 12 is a conceptual cross-sectional view of a part of an example ofan inner liner 50 of a catheter body, where the cross-section is takenthrough a center of the inner liner and along a longitudinal axis 16 ofinner liner 50. In some examples, the plurality of cuts defined in aliner wall of inner liner 50 include one or more slits 52. A slit may bea cut in inner liner 50 where no material is removed. Slits 52 may bepartial slits that only extend partially through a thickness of a linerwall of inner liner 50. In these examples, slits 52 may extend from aninner surface of inner liner 50 towards the outer surface or may extendfrom the outer surface of inner liner 50 towards inner lumen 26. Inother examples, slits 52 may be through-slits that extend through theentire thickness of the liner wall. Slits 52 may have any suitablearrangement and configuration, including those described with referenceto cuts above and below.

Cuts 20 defined in distal section 18B of inner liner 18 of a catheterbody 12 may be sized, shaped, and arranged to increase a bendingflexibility of distal section 18B and a corresponding distal portion ofcatheter body 12. In some examples, each cut of the plurality of cuts 20are substantially the same size and shape (e.g., designed to be the samesize and shape, but due to manufacturing variances, may slightly differin size and/or shape). The shape of the cut may refer to characteristicssuch as a shape of the ends of the cut (e.g., rounded or squared ends),the direction of elongation relative to longitudinal axis 16, orcross-sectional profile. In addition to the pattern of cuts 20, thearrangement of cuts may also refer to a density of cuts 20 along innerliner 18, which may be a number of cuts per unit length of inner liner18 (measured along longitudinal axis 16).

FIGS. 13-17 illustrate example cut patterns, sizes, shapes, anddensities of cuts defined in liner wall of the inner liner. FIG. 13 is aperspective view of an example inner liner 54 that defines plurality ofthrough-cuts, e.g., 56, 58A-58E, 60, which each fully extend through athickness of liner wall 62 of inner liner 54 and expose inner lumen 26.In other examples, one or more of the cuts 56, 58A-58E, 60 may bepartial cuts, which do not fully penetrate through the thickness ofliner wall 54. In the example of FIG. 13, the cuts defined by innerliner 54 are arranged as a plurality of sets of cuts that are axiallyspaced from one other (in a direction along longitudinal axis 16). Eachset of cuts may include a plurality of axially aligned cuts axiallyaligned with each other (aligned longitudinal axis 16) andcircumferentially offset from each other. For example, a first set ofcuts may include cut 56 and the cuts shown in FIG. 13 as being axiallyaligned with cut 56, a second set of cuts may include cuts 58A-58E, anda third set of cuts may include cut 60 and the cuts shown in FIG. 13 asbeing axially aligned with cut 60.

In the example of FIG. 13, the sets of cuts are substantially similar(in number of cuts, size of cuts, shape of cuts, and the like), but thecuts of each set may be longitudinally and circumferentially offset fromthe cuts of an immediately adjacent set. For example, cuts of the firstset of cuts are longitudinally and circumferentially offset from thecuts of the second set of cuts. As shown in FIG. 13, cut 56 of the firstset is not circumferentially aligned with any of cuts 58A-58E of thesecond set, but, rather, is offset from cuts 58A and 58E by an anglebetween about 5 degrees and about 90 degrees. In the example shown inFIG. 13, the cuts of adjacent sets are circumferentially offset from oneanother by about 30 degrees.

Thus, in the example shown in FIG. 13, adjacent sets of cuts arecircumferentially rotated 30 degrees relative to each other. Othercircumferential offset values may be used. In some examples, the cuts ofadjacent sets are circumferentially offset from one another by about 5degrees and about 90 degrees (e.g., about 15 degrees or about 45degrees).

In the example shown in FIG. 13, every other set of cuts issubstantially aligned circumferentially. For example, cut 56 of thefirst set may be circumferentially aligned (but axially offset) from cut60 of the third set.

Circumferentially offsetting adjacent sets of cuts may help improve thestructural integrity of inner liner 54, e.g., may make inner liner 54less likely to kink in response to a given bending force compared toinner liner 54 including adjacent sets of cuts that arecircumferentially aligned. In addition, offsetting adjacent sets of cutsmay help improve the radial distribution of forces in inner liner 54when external pressure is applied to inner liner 54, due at least inpart to the more omnidirectional flexural stiffness. The more the cuts(e.g., 56 or 60) are circumferentially aligned, the more unidirectionalthe flexural stiffness.

Each set of cuts may have any suitable number of cuts, such as, but notlimited to the five shown in FIG. 13, or fewer than five or greater thanfive. Cuts of the same set may share a circumferential axis. Otherconfigurations of sets of cuts may be used. For example, the sets ofcuts shown in FIG. 13 may be circumferentially aligned, such that cutsof each set are directly adjacent to aligned with a cut of an adjacentset.

FIG. 14 is a perspective view of inner liner 66 defining a cut patternthat includes a plurality of cuts 68. The cut pattern in the example ofFIG. 14 may be similar to the cut pattern in FIG. 13, and may includemultiple sets of cuts, where each set is displaced from an adjacent setboth longitudinally and circumferentially. Some characteristics of cuts68 in the example of FIG. 14 may be different than the cuts of theexample of FIG. 13. For example, the width of cuts 68 may be greaterthan the width of cuts shown in FIG. 13, and the length of cuts 68 maybe smaller than the length of cuts shown in FIG. 13. As another example,a cut density of cuts 68 may be less than a cut density of cuts shown inFIG. 13. However, due to the wider width of cuts 68, the overallpercentage of inner liner 66 shown in FIG. 14 that is cut may be thesame as or greater than the overall percentage of inner liner 54 shownin FIG. 13 that is cut.

FIG. 15 is a perspective view of inner liner 70 and illustrates anexample cut pattern that includes a plurality of cuts, which include afirst set of cuts 72 and a second set of cuts 74. In the example shownin FIG. 15, the sets of cuts 72, 74 are on opposite sides of a medianplane 75 which bisects inner liner 70 along longitudinal axis 16. Insome examples, the sets of cuts 72, 74 on either side of median plane 75may mirror each other, such that there is mirror symmetry in cuts 72,74. In other examples, the sets of cuts 72, 74 on either side of medianplane 55 may have other symmetrical arrangements. The cuts of the setsof cuts 72, 74 may be through-cuts or partial cuts. In other examples,one or both sets of cuts 72, 74 includes both through-cuts andpartial-cuts. The symmetry in the cuts may extend to the type of cut,and not just the location of cuts.

FIG. 16 is a perspective view of an example inner liner 76 andillustrates an example of a cut pattern in inner liner 76. The cutpattern shown in FIG. 16 includes a plurality of through-cuts cuts 78,including through-cuts 78A, 78B, and 78C, which each fully extendthrough a thickness of liner wall 79 and expose inner lumen 26. In otherexamples, one or more of the cuts 78 may be partial cuts, which do notfully penetrate through the thickness of liner wall 79. In the exampleof FIG. 16, cuts 78 have both radial and longitudinal components. Forexample, the ends of each of the cuts 78 are both longitudinally andcircumferentially offset from each other, such that each of the cuts 78extends both longitudinally and circumferentially around inner liner 76.In contrast, the ends of cut 58 (FIG. 13) are longitudinally aligned,but circumferentially offset from each other. Angular orientation ofcuts 78 include angles of about 10 degrees to about 80 degrees (usingthe framework shown in FIG. 7) relative to longitudinal axis 16, ineither clockwise or counterclockwise directions. In an example, theangular orientation of cuts 78 is about 30 degrees relative tolongitudinal axis 16.

Cuts 78 may each extend around any suitable percentage of the outercircumference of inner liner 76. For example, ends of a cut 78 may belongitudinally offset, but circumferentially aligned, such that the cut78 extends around 360 degrees of the outer circumference of inner liner76. As another example, ends of a cut 78 may be both longitudinally andcircumferentially offset, such that the cut 78 extends around less than360 degrees of the outer circumference of inner liner 76.

In some examples, at least some cuts 38 may be partially or fullycircumferentially aligned with another cut. For example, cuts 56, 60shown in FIG. 13 are longitudinally offset from each other, but fullycircumferentially aligned (e.g., such that the ends of the cuts 56, 60have the same circumferential position relative to an outercircumference of inner liner 18, as described using the framework shownin FIG. 8). In contrast, cuts 78A, 78B are partially circumferentiallyoffset from each other, but also partially circumferentially aligned. Anend portion of cut may, for example, circumferentially overlap with anend portion of adjacent cut 78B.

In the pattern shown in FIG. 16, adjacent cuts 78 (e.g., cuts 78A, 78Bor cuts 78B, 78C) may be circumferentially offset from one another byabout 5 degrees to about 90 degrees (such as about 30 degrees to about60 degrees or about 45 degrees, using the framework shown in FIG. 8). Inother examples, however, adjacent cuts 38 may be fully circumferentiallyaligned.

In the example of FIG. 16, cuts 78 are substantially similar (e.g.,similar or nearly similar sizes and shapes) to each other. In otherexamples, however, at least some cuts 78 may have a differentconfiguration than each other. For example, at least one cut 78 may havea different length, width, or depth than another cut 78.

In addition, in the example cut patterns shown in FIGS. 2, 13, 14, 15,and 16, the cuts (generally referred to herein as “cuts 20”) of innerliner 18 are substantially evenly (e.g., evenly or nearly evenly) spacedfrom each other along longitudinal axis 16. In these examples, innerliner 18 may have a uniform density of cuts 20. A uniform density ofcuts 20 may provide a distal section 18B of inner liner 18 that exhibitssubstantially uniform bending flexibility and tensile strength. In otherexamples of inner liner 18, however, inner liner 18 may define a cutpattern that includes an increasing or decreasing density of cuts 20along longitudinal axis 16, towards a distal end of inner liner 18. Toachieve an increasing density of cuts 20, cuts 20 adjacent to each otherin the longitudinal direction may be spaced closer to each other, suchthat there are more cuts 20 per unit length of inner liner 18. Toachieve a decreasing density of cuts 20, cuts 20 adjacent to each otherin the longitudinal direction may be spaced further part, such thatthere are fewer cuts 20 per unit length of inner liner 18.

Any of the cuts in inner liner 18 described herein may also have auniform width and thickness along its length. In other examples, a cutin inner liner 18 described herein may also have a varying width and/orthickness along its length. For example, in FIG. 16, one of the cuts 38may be deeper along a medial portion than at the end portions, thegreater depth resulting in greater bending flexibility of inner liner 76at the medial portion of the cut 78.

As discussed above, in some examples, inner liner 18 defines a pluralityof cuts 20 (e.g., as shown in FIGS. 13 to 16), while in other examples,inner liner 18 defines only one cut (a single cut). The single cut mayinclude both circumferential and longitudinal components in someexamples. FIG. 17 is a perspective view of an example inner liner 80that includes a single cut 82 that has both circumferential andlongitudinal components. For example, single cut 82 may have a helicalconfiguration that spirals around the circumference of inner liner 80about longitudinal axis 16. Cut 82 may be a partial cut and/or athrough-cut. In some examples, cut 80 defines a helix having a pitch ofabout 1 mm to about 5 mm between adjacent turns of the cut, although ahelical cut defining outer pitches may be used in other examples.

Cuts, as described herein, may comprise multiple portions, such that afirst portion includes a through-cut, and such that a second portionincludes a partial cut. For example, cut 82 in the example of FIG. 17may comprise multiple portions, where some portions of cut 82 arethrough-cut portions and other portions of cut 82 are partial cutportions. These portions may have any suitable arrangement relative toeach other. For example, the through-cut portions of cut 82 may bepositioned between two partial cut portions of cut 82. As anotherexample, a partial cut portion of cut 82 may be positioned between twothrough-cut portions of cut 82.

FIG. 18 is a conceptual cross-sectional view of a part of an example ofinner liner 80 of a catheter body, where the cross-section is takenthrough a center of the inner liner and along a longitudinal axis 16 ofinner liner 80. In an example, helical cut 82 wraps around inner liner80. Although illustrated with relatively evenly spaced cycles aroundinner liner 80, in some examples, such a helical pattern may include anincreasing density of cycles in the direction of longitudinal axis 16.

The catheter bodies described herein may be formed using any suitabletechnique. FIG. 19 is a flow diagram of an example method of formingcatheter body 12. In accordance with the technique shown in FIG. 19, aplurality of cuts 20 are defined in inner liner 18 (90). Any suitabledevice may be used to form inner liner 18 defining a plurality of cuts20. In some examples, the cuts are formed into a tubular body. Forexample, a mechanical cutting tool, such as a rotating blade, may beused to define cuts 20 in the tubular body. As another example, a lasercutter may be used to define cuts 20 in the tubular body to form innerliner 18.

In some examples in which a laser cutter is used, inner liner 18 may bepositioned over a mandrel. In some examples, inner liner 18 is aunitary, seamless body, and may be positioned over the mandrel by atleast inserting the mandrel through an end of inner liner 18. A laser(e.g., a carbon dioxide laser cutter) may then be used to define cuts20. One or more parameters of the laser may be adjusted in order tomodify the characteristics (e.g., a shape, depth, width, and/or length)of the cuts being defined in inner liner 18. For example, a power of thelaser, a focal point of the laser, an ultraviolet wavelength of thelaser, or a speed of movement of the laser relative to inner liner 18may be modified in order to achieve the desired cut size and pattern. Awidth of a cut 20 may be a function of a focal width of the laser. Inaddition, a depth of the cut may be a function of the ultravioletwavelength or speed of the laser relative to inner liner 18. Further, asuitable depth of the cut may be achieved by repeated laser rastering,such as over the same path.

In other examples, inner liner 18 defining a plurality of cuts 20 isformed using additive manufacturing techniques, such asthree-dimensional printing. As another example, inner liner 18 may beformed by depositing an inner liner material (e.g., PTFE) over a mask,where the mask shape defines the location and size of the cuts 20. Thematerial may be deposited using any suitable technique, such as, but notlimited to, spray deposition, dip coating, or the like. In someexamples, the material is deposited in layers (e.g., 1-2 microns thick)and liner wall 19 is formed by building-up a plurality of layers.

In the example shown in FIG. 19, inner liner 18 is stretched (92). Innerliner 18 may be stretched at different points in time relative to thedefinition of a plurality of cuts in inner liner 18 (90). For example,stretching inner liner 18 can occur prior to defining a plurality ofcuts in inner liner 18 (90) or after defining a plurality of cuts ininner liner 18 (90). In some examples, the defining of cuts (90) andstretching (92) may be performed more than once, such as firststretching the inner liner, then defining a plurality of cuts, thenstretching the inner liner again. In some examples, inner liner 18 isformed by ram extruding the liner material (e.g., PTFE) or film castingthe liner material, and cuts 20 may be made in inner liner 18 afterinner liner 18 is extruded but before the inner liner is stretched.Stretching inner liner 18 may help increase an axial strength of innerliner and thin liner wall 19, e.g., from about 0.033 mm to about 0.020mm. In other examples, cuts 20 may be made in inner liner 18 after innerliner 18 is extruded and stretched. After being stretched, the length ofinner liner 18 may be longer and the liner wall thickness may besmaller. A thinner liner wall 19 may result in a softer and moreflexible inner liner 18. In other examples of the technique shown inFIG. 19, inner liner 18 may not be stretched.

If catheter body 12 includes support member 28, support member 28 may bepositioned around inner liner 18 before or after being stretched. Asshown in FIG. 19, outer jacket 24 may be positioned around inner liner18 (and support member 28 if present) (94). Outer jacket 24 may beconnected to inner liner 18 using any suitable technique. For example,outer jacket 24 may be heat shrunk around inner liner 18. A suitabletechnique for connecting outer jacket 24 to inner liner 18 may include,heating outer jacket 24 while outer jacket 24 is in heat shrink tubingenough to cause the material of outer jacket 24 to melt, then reflow thematerial of outer jacket 24. Other techniques may also be used toconnect outer jacket 24 to inner liner 18.

Catheter 10 may be used for medical procedures. For example, a guidewiremay be introduced into a patient. Catheter body 12 may be introduced inthe patient over the guidewire. In an example, a medical device may beintroduced into inner lumen 26 of catheter body 12. In an example,catheter 10 may be used for aspirating a thrombus. In an example, distalend 12B of catheter body 12 may be introduced into an intracranial bloodvessel, and a thrombus may be removed from the blood vessel throughinner lumen 26 of catheter body 12, such as via aspiration or using athrombus retrieval device.

In some cases, catheter body 12 is advanced over an inner catheterhaving a smaller outer diameter than catheter body 12, rather thandirectly over a guidewire. The inner catheter may, for example, helpfill the space between the guidewire and the outer surface of outercatheter body 12 to help minimize the ledge effect, which may occur whena distal tip of catheter body 12, particularly the portion of the edgeof the tip that tracks along the outside of a curve formed by the body12, engages with or tracks along a wall of vasculature as catheter body12 is advanced over a guidewire through a curve in the vasculature. Theledge effect may, at least in part, be attributable to unopposed spacebetween the guidewire and lumen 26 of catheter body 12. In someexamples, catheter body 12 that includes inner liner 18 formed from PTFEmay define opening 13 that is configured to resist geometric deformationmay allow catheter body 12 to be guided through vasculature over aguidewire, without need for an inner catheter. Cuts 20 defined in innerliner 18 may help improve the navigability of the PTFE inner liner byincreasing the bending flexibility of distal section 18B of inner liner18. The elimination of an inner catheter may not only reduce costsassociated with the medical procedure, but may also reduce the timerequired to reach the target tissue site as a step of guiding the innercatheter to the tissue site before guiding catheter 10 to the targettissue site may be eliminated.

The examples described herein may be combined in any permutation orcombination.

Various aspects of the disclosure have been described. These and otheraspects are within the scope of the following claims.

What is claimed is:
 1. A catheter comprising: an elongated bodyincluding: an inner liner extending between a proximal end and a distalend, the inner liner defining a lumen, wherein the inner liner includesa proximal section including the proximal end and a distal sectionincluding the distal end, wherein the distal section of the inner linerincludes a liner wall defining a plurality of cuts; and an outer jacketpositioned over the inner liner and fixed to the inner liner, whereinthe outer jacket extends over the plurality of cuts, and wherein theinner liner is formed from a more lubricous material than the outerjacket.
 2. The catheter of claim 1, wherein the lumen defined by theinner liner is an inner lumen of the elongated body.
 3. The catheter ofclaim 1, wherein at least one cut of the plurality of cuts is athrough-cut that extends through a thickness of the liner wall to thelumen.
 4. The catheter of claim 1, wherein at least one cut of theplurality of cuts is a partial cut, wherein the partial cut extends onlypartially through a thickness of the liner wall.
 5. The catheter ofclaim 4, wherein the at least one cut extends from an outer surface ofthe liner wall and radially inward towards the lumen.
 6. The catheter ofclaim 4, wherein the at least one cut extends through about 20% to about80% of the thickness of the liner wall.
 7. The catheter of claim 1,wherein at least one cut of the plurality of cuts is disposed in an arcaround an outer surface of the inner liner.
 8. The catheter of claim 1,wherein at least one cut of the plurality of cuts is elongated in adirection substantially perpendicular to a longitudinal axis of theinner liner.
 9. The catheter of claim 1, wherein at least one cut of theplurality of cuts is oblong shaped, a major axis of the oblong shapeextending in a direction substantially perpendicular to a longitudinalaxis of the inner liner.
 10. The catheter of claim 1, wherein each cutis elongated in a direction that defines an angle from about 45 degreesto about 90 degrees relative to a longitudinal axis of the inner liner.11. The catheter of claim 1, wherein at least one cut of the pluralityof cuts is elongated in a direction substantially parallel to alongitudinal axis of the inner liner.
 12. The catheter of claim 1,wherein the inner liner has a circular cross-section, and at least onecut of the plurality of cuts extends around only part of a circumferenceof the circular cross-section.
 13. The catheter of claim 1, wherein adensity of the plurality of cuts decreases in a proximal direction,wherein the density corresponds to a number of cuts per unit length ofthe inner liner.
 14. The catheter of claim 1, wherein the cuts aresymmetrically arranged relative to a longitudinal axis of the innerliner.
 15. The catheter of claim 1, wherein the cuts are asymmetricallyarranged relative to a longitudinal axis of the inner liner.
 16. Thecatheter of claim 1, wherein a distal-most cut of the plurality of cutsis arranged between about 0.02 centimeters and about 30 centimeters fromthe distal end of the inner liner, and wherein a proximal-most cut ofthe plurality of cuts is about 5 centimeters to about 35 centimetersfrom the distal end of the inner liner.
 17. The catheter of claim 1,wherein the elongated body extends along a longitudinal axis, whereinthe inner liner comprises an inner liner portion and the outer jacketcomprises an outer jacket portion longitudinally aligned with the innerliner portion, wherein the inner liner portion is formed from a firstmaterial having a first hardness and the outer jacket portion is formedfrom an outer liner material having a second hardness, the secondhardness being greater than the first hardness.
 18. A cathetercomprising: an elongated body including: an inner liner extendingbetween a proximal end and a distal end, the inner liner defining alumen, wherein the inner liner includes a proximal section including theproximal end and a distal section including the distal end, wherein thedistal section of the inner liner includes a liner wall defining ahelical cut; and an outer jacket positioned over the inner liner andfixed to the inner liner, wherein the outer jacket extends over thehelical cut, and wherein the inner liner is formed from a more lubricousmaterial than the outer jacket.
 19. The catheter of claim 18, whereinthe lumen defined by the inner liner is an inner lumen of the elongatedbody.
 20. The catheter of claim 18, wherein the helical cut is athrough-cut that extends through a thickness of the liner wall to thelumen.
 21. The catheter of claim 18, wherein the helical cut is apartial cut extending only partially through a thickness of the linerwall.
 22. The catheter of claim 18, a proximal end of the helical cut isabout 5 centimeters to about 35 centimeters from the distal end of theinner liner.